This is Money's inbox has been inundated with e-mails from angry passengers, still fighting for a payout.

But one airline pops up more than others in there – KLM.

KLM Royal Dutch Airlines, the national airline of Holland and part of Air-France KLM, is the oldest carrier in the world still operating under the same name, after it was founded in 1919. Longevity does not appear to go hand-in-hand with transparency in this case though.

The rules on ash cloud delay compensation

Under EU rules, airlines have a duty of care to look after stranded passengers, even if cancellations were due to exceptional circumstances out of their control. The volcanic ash was an exceptional circumstance, and KLM is an EU airline.

But KLM is taking a hard line in interpreting the rules.

At the height of the disruption, The Air Transport Users Council (AUC) reminded passengers of their rights. It said: 'Regulation (EC) 261/2004 requires airlines to offer you meals, refreshments and hotel accommodation as appropriate whilst you wait for a rearranged flight.

'They should also cover any transport costs between the hotel and the airport. There are no time or monetary limits on the provision of this assistance.

'If your airline has not provided assistance, and you have had to arrange it yourself, our advice is to keep your expenditure to a minimum, make sure you get receipts and claim reimbursement from your airline when you get home.'

KLM is one of the world's most established airlines in the world and you'd expect it to fall in line with the above EU rules – but hearing some of the responses This is Money readers have had, it appears otherwise.

We caught up with some customers who are still chasing KLM, despite the difficulties in getting a straight answer from them.

In many cases, they told us they had found KLM to be obstructive, to have given incomplete or misleading information and if they had offered compensation it was for only the first night not the full delay, which the AUC says they should cover.

This is Money knows first hand how difficult it is to contact KLM, with a phone call first made at the end of May to ask about reader's difficulties, when they advised us to send an e-mail

We didn't receive a response, despite highlighting a number of problems. Eventually, after various phonecalls and e-mail requests for a comment, we got the following from the airline.

A spokeswoman for KLM, said: 'We are aware of the EU law requiring refunds and are handling the queries on a case-by-case basis. Everyone can of course fill out the compensation forms on our website.

'Every single case is being judged on the individual situation and each case is getting a reply.'

When probed about whether any full expenses claims had been paid out, she said: 'I cannot discuss individual cases regarding expenses, but people are being reimbursed on a case-by-case basis. We are, as you can understand, very busy and there are other airlines that are also competing with the problems of the EU rules.

'Our care and assistance policy is very good compared to other airlines, and the EU is going to change the rules shortly. It should be handled the same in every country so we're on a level playing field.'

The problem that passengers face is that the only way to force airlines to pay EU compensation is to take them to court. It is possible to do this via the small claims court and we have a guide on how to do this here.

A Civil Aviation Authority (CAA) spokesman said: 'KLM is an EU airline, and is fully signed up to the directive. Each country regulates its own airlines, so for instance we look after BA. The Dutch civil authority will look after KLM passengers.

'The regulation states that a refund is necessary for reasonably accrued expenses, but it is a complicated directive.

'We speak to the British airlines on a weekly basis and are available for any queries they may have in regards to the laws and rules, and so far we haven't had to take further action against any airline.'

'We recommend going to the new EU commission website, and finding the details of the Holland enforcement agency.'

Forcing KLM to pay up though will take time and patience and it is highly likely many passengers will simply write off their expenses or take whatever the airline offers them, as at least it is something.

That, however, is not acceptable says one travel expert, as KLM benefit from being an EU carrier and should therefore abide by the rules.

'It is outrageous that airlines such as KLM are shirking their clear legal responsibilities to passengers who were out of pocket from flight disruption as a result of the Icelandic volcano,' says Bob Atkinson, of Travelsupermarket.com

'Regardless of whether the EU261 is fit for purpose, KLM are clearly flouting the letter of the law here and showing disregard for their customers and legal obligations. They have abandoned customers without help at a time when they needed them most.

'The EU commission needs to come down heavy on airlines such as KLM in order to protect customers who can ill afford the expense they have gone to in order to get home'

This is Money will be keeping tracks on KLM and its passengers problems and pushing for them to get a fair deal. Below are some of their stories.

The KLM ash cloud nightmares

Stranded in the States with four small children

Eric Mason jointly started a Facebook campaign 'KLM must support passengers stranded by ash cloud,' after KLM refused to refund expenses he incurred.

Eric and his party of seven (four of his family, three in another family) were delayed for a week in Atlanta. Four members of this party were small children. His in-laws, also in Atlanta, were stranded for nine days.

Upon discovery of the ash cloud, they rang KLM repeatedly and were told to head for the six hour journey to the airport as their flight was still on schedule. As they travelled to the airport, the flight was cancelled.

They tried calling KLM but Eric explains: 'Their phone lines couldn't cope – apparently they switched off their international lines completely and didn't restore it until the following morning.'

When they arrived home, they discovered the EU rules and ability to claim for expenses. But Eric adds: 'KLM wouldn't tell us how to claim.

'We had been renting homes and decided that as we were not receiving any help we would move to cheaper accommodation near the Atlanta area as we hadn't budgeted for the extra time away.'

'In total, our family of four spent around $2,000 including food, accommodation, food, airport transfers and phone calls.' After numerous letters and scanning receipts for the expenses, they finally received an offer of just €400 for one night.

Eric said: 'There were many messages back and forth including me telling them I would take them to court. They told me that they didn't believe the EU legislation covered this and that I could take them to court.'

With other campaigners on the Facebook page, he said: 'We've written to many different groups; we've been told that the AUC are waiting for answers from KLM. The Danish and Dutch version says the same thing, the EU Transport Minister passes the message on to the enforcement bodies but still we wait.'

William Lyall and his wife were stranded in Dallas for five nights, when their flight back to Edinburgh was cancelled.

They ran up a bill of $405.71 for hotels and $145 for food. Being conscious of running up a big bill, they stuck to a budget hotel and standard restaurants to keep their expenses to a minimum.

He said: 'When I got back I sent a letter on April 27 complete with my invoices. They never acknowledged this letter, and luckily I copied all of the invoices. I know they received it, as I sent it recorded delivery to the UK head office and someone signed for it.

'All-in-all, I have sent them eight e-mails and a handful of letters. I hadn't heard from them until recently. It was a few weeks ago, via an e-mail saying to re-send my invoices. They didn't even put in the e-mail where to send them to.

'I e-mailed back and was informed to send the originals to the France head office and they have offered to pay me back one night expenses. It's not good enough, so I ignored that.

'The claim has taken almost three months which is shocking; I can't see how it could take them so long. However I have to say, the KLM staff in Dallas were really good, but there was nothing they could do to help. But the rest of the organisation has been very poor.'

KLM told us 'it's not our fault, we don't have to do anything thing'

Tony Williams, his wife and daughter arrived in Schiphol Amsterdam airport on April 15, en route from Singapore. They were trapped there until KLM told them to make their own way home, which they did on April 20.

To add insult to injury, his daughter celebrated her 18th birthday in an airport surrounded by angry customers and disgruntled staff.

Tony said: 'KLM did start out providing camp beds and refreshments but then their priority became to empty the airport and close everything down, which they successfully did aside from a Starbucks and a small eatery.'

Euroline offered coach services to get passengers to the ferry ports. Tony said: 'KLM refused to call them or set up coaches. They kept saying 'it's not our fault, we don't have to do anything' and told us to make our own way home.'

They took KLM at their word and made their own way home: A train to Brussels, a hotel overnight, the Eurostar to St. Pancras, a taxi to Paddington and finally a train to Taunton.

They incurred a total expense of £1,400, while KLM have offered them a good will gesture of €250.

Tony added: 'The customer services is dire, the phone just rings, they give you reference numbers and nothing happens. They won't give me anything in writing and the only way they get back to you quickly seems to be if you tell them you're taking them to court.'

Tony was informed that the legal department at KLM are taking on the EU legislation and that nothing much can be done until it's over, but he believes that 'they shouldn't penalise people now, they should challenge it afterwards.'

He remains confident that KLM will have to payout, and said: 'I'm sure we'll get our money back, it's just a matter of when.'

Caught out in Cape Town for 13 days

A passenger, who wishes to remain anonymous, not wanting to jeopardise the hope of a refund, says he no longer trusts the company. He has been chasing KLM for months with no avail.

Not only this, he has even written to his local MP Stephen Williams, and MEP Ashley Fox, who took up his case. They too have been given very limited response from the airline.

He and his wife were left stranded in Cape Town for 13 days due to the disruption. The cost of accommodation and other essentials came to over £1,000 for the both of them.

He said: 'I sent claim forms to their UK office and e-mailed the claims via their website. In the end, they've said they are only prepared to pay for the first night, at a rate of £100 each. It's insane.

'I appreciate it was out of their control, but they surely have insurance policies that allow for this type of thing. They are a public limited company, behaving badly.'

As well as contacting MPs, he has filled in complaint forms to the institute of transport in both Holland and France. However, he is told it can take six months for a response.

He added: 'KLM are a bunch of cowboys. It's like buying a car, finding out it doesn't work, and then not getting a refund.'

He did receive one response from them after he pointed out that under European law they were responsible for claims regardless of the cause. He was told: 'Yes we know, but that is the decision of the directors.'

Internet tales of KLM woe

The internet is full of more tales of KLM woe, with forum users helping each other out and sharing their experiences with the airline.

On the website www.flyertalk.com, one user, eslick, is appearing to be at the end of their tether. They said: 'It looks like we're off to the small claims court. Three messages from KLM at the end of last week, one the same as they had sent before word for word, next saying really the same and the third one below: (e-mail from KLM)'Whilst it is always a matter of concern to us when customers remain dissatisfied, I regret that we are unable to make any further compensatory or goodwill gesture in this case.

'Our previous goodwill offer to reimburse your expenses corresponding to your first night of accommodation, as well as any additional necessary costs for that night to the value of Euro, remains available to you on receipt of the bank details we already requested from you. Your case will remain pending until such time as we receive these.

'Despite your present sentiment, I hope you will feel able to choose KLM again in the future.'

Are you still waiting for compensation from an airline for the volcano disruption? Have you received a reimbursement from KLM for any disruption? Do you feel KLM well within their rights to not pay out full expenses? We'd love to hear from you…